> Protobuf is intentionally designed to NOT require any parsing at all.
As others have mentioned, this is simply not the case, and the VARINT encoding is a trivial counterexample.
It is this required decoding/parsing that (largely) distinguishes protobuf from Google's flatbuffers:
https://github.com/google/flatbuffers
Cap'n Proto (developed by Kenton Varda, the former Google engineer who, while at Google, re-wrote/refactored Google's protobuf to later open source it as the library we all know today) is another example of zero-copy (de)serialization.